[Test] MiniNode: Coerce OP_PUSHDATA bytearrays to bytes

If a bytearray is passed in as part of an iterable, the CScript constructor
fails because b''.join() cannot be used to join a bytearray to a bytes or str in
Python 2.

qa/rpc-tests/test_framework/script.py

@@ -666,7 +666,7 @@ class CScript(bytes):
             else:
                 other = CScriptOp.encode_op_pushdata(bignum.bn2vch(other))
         elif isinstance(other, (bytes, bytearray)):
-            other = CScriptOp.encode_op_pushdata(other)
+            other = bytes(CScriptOp.encode_op_pushdata(other))
         return other
 
     def __add__(self, other):